Now let's check out "Blue Ball Shuffle". This is a 12-bar Texas shuffle blues in A. What's unique about it is that you're playing the upbeats of the rhythm, and you double part of the bass line. It's fast, and you have to really nail the upbeats and the bass line together.

Mixing the rhythm guitar part with the bass line is something that Stevie Ray Vaughn did all the time. The progression goes I-IV-V, with leading chords taking you back to the I.